System of current control for plural translating devices



Feb. 27, 1951 2,543,114

G. J. LEXA SYSTEM OF CURRENT CONTROL FOR PLURAL TRANSLATING DEVICES Filed Dec. 1, 1948 REGULATOR A $3 ja Patented Feb. 27, 1951 SYSTEM OF CURRENTOONTROL FOR; PLURAL TRANSLATI-NG DEVICES George J. Lexa, Wauwatosa Wis.,. assignor to.-

Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of DeIaware Application December 1, 1948, SerialNo. 62,814

8 .Claims., 1

This invention relates tov a system of current control for plural translating devices. The invention relates more particularly to apparatus for control of the. magnitude of the current: supplied to a plurality of translating devices connected to a three-wire supply circuit; and although not limited thereto is. especially adapted for control of the light intensity of a plurality of; incandescent lamps or groups of lamps Heretofore many systems: have been proposed;

for controlling the light intensity of incandescent.

troll-ing the voltage impressed thereon, but all.

such systems have certain disadvantagesas-will be pointed out hereinafter, and the present:sys-.- tem isso designed as to overcome such disadvantages.

In accordance with my invention the lampsa-re connected in series with one of the windings of a regulating transformer, which has another winding connected across the outer wires of a three-wire supply in series with a pair of electron tubes Whose main electrodes areconnected: in inverse-parallel. To control the lamp current, the tubes are provided with control electrodes by means of which the effective impedance of said tubes is controlled.

An object of the invention-is to provide a system operable automatically to elfect simultaneous adjustment of the voltagesim-pressed upon two translatingdevices, one of whichdevices isconnected between the neutral wire and one out. Side wire and-the other of which devices isconnected between said neutral wire and the other outside wire of a three-wire supply circuit, through ranges each between a low minimumvoltage and values substantially equal to the line voltage of the supply circuit.

Another object is to provide a control system of the aforementioned character wherein the translating devices are electric lamps or groups of electric lamps, whereby the voltages impressed upon the respective lamps or group of lamps can be adjusted throughout ranges from below the voltages at which the respective lamps emit visible light to voltages equal to or above the line voltage.

Another objectis to provide a three-wire system of the aforementioned type in which the voltages impressed upon the lamps of the two halves of the system remain equal even-though the lamp loads of the two halves of'thesystem differ to a large degree with respect to each other..

Another object is to providea system which affords a maximum range of regulation for all loads between no load and, the. maximum load for which the system, is, des gned;

Otheraobjectsand advantages will appear hereinaften.

The. accompanying; drawing, consisting of a single figure, diagrammatically and schematically illustrates a, preferred embodiment of the; invention, wherein the, translating devices are connected in series circuit between each end of a center-tapped winding of a, transformer and the respective outer wires ofra three-wire source. of supply; the neutral wire of said three-wire source of supply being connected to said center-tap; andthe otherrwi-ndin ofv Saidtransformerbeing connected in series with the inverse-parallel con-v ncctedipairof; electron tubes across the outside wires of said, sourceof supply.

Referring to the drawing, the same illustrates a, three-wire, alternating; current supply system comprising: outside lines L and L and a neutral line- L2; It may be assumed thatv the nominal voltage between lines L and: L is 220 volts, and hence thatthe voltage of each half of the system isllO. volts. The lamp or group of lamps illustrated diagrammatically at, I0, is connected in series with the left-hand end of winding H of transformer 12 to line L and the lamp or group of lamps designated; by numeral Illa is connected in series; with therlght-hand end of winding l I toline L Assuming; thatv the numerals l0 and lll 'represent groups of lamps, it is to be understood that theljampsof the respective groups may be: connected in any desired relationship to each other; such as in seriesror in parallel, or some in each relationship. Winding ll is provided with a center-tap I l -to which-the neutral line L is connected.

The winding l3'of transformer I2 is connected in series with the inversely-parallel connected tubes [4, whichare shown as gaseous electron tubes of the triode type, across the outer wires Ii -and L of the -thre e-wire-. source of supply. It isrto bel-understood, oiccourse, that other types of tubes, suchas. ignitron tubes, may be; employed if ;desi-re.d

The. conductivity of said tubes I4 is controllable in; a .well' known; manner through control electrodes, thepenergizationrof which is in turn controlled. by a suitable regulator [5 of any well known type; Therregulatorali; controls the phase Ofithfi control electrode potential with respect to. the cathode ottherespective tube. Regulation of the control electrode potential varies the, impedance of therespective tube andthus the cur:- rentv'whi'ch' flows. inthe, windingv l3.

By employment of a single transformer l2 connected as illustrated in the drawing the effect of unbalanced lamp loads (at 10 and W is ubstantially eliminated. Operation of the system illustrated is such that the lamp voltages in the two sections of the three-wire system are substantially balanced even though the values of the lamp loads in the two sections differ greatly from each other. This, as will be readily understood, is due to the fact that the voltages induced in the two sections of the winding H are at all times substantially equal to each other, so that the net resultin lamp voltages are likewise balanced.

When the tubes I4 are non-conducting the impedance of the transformer I2 is obviously a maximum. Hence the inductive impedances in series with the lamps l0 and l are also a maximum and the lamp voltage a minimum. The transformer I2 is so constructed and the arts thereof so proportioned that under these conditions the lamp current is below the value at which the lamps emit any visible light. On the other hand, when the tubes l4 become conducting, a voltage is induced in the winding H which is in opposition to the reactance drop due to the lamp current, so that the voltage impressed upon the lamps gradually increases as the conduction of the tubes I4 is increased until for full conduction of the tubes the voltage induced in the winding H by the current in winding I3 is added to the line voltage. It is therefore obvious that the lamp voltage may be increased above the line voltage. This increase depends upon the impedance of the transformer I2 and that of the tubes l4.

With a system of the character illustrated, the lamp voltage for 110 volt line voltage on both sides of the neutral line L could be raised to 135 volts; and the resultant voltage unbalance between the two sections of the system with full lamp load on one section and no load on the other section would be only 2.6 per cent of the nominal line voltage.

In a test upon a system like that herein illustrated, in which the line voltage and lamp loads were the same as those aforementioned, and the winding l3 had one-half of the number of turns in the winding II, it was found that the anode voltage of the tubes I 4 varied from 340 volts to 210 volts, and the maximum lamp voltage was 135 volts, whereas the minimum lamp voltage was below the blackout voltage as aforedescribed. The control current variation was only from zero to 3.7 ma. as observed at regulator l5. It will thus be seen that in accordance with my invention the range of anode'voltage variation required for the tubes I4 is very small; and the maximum anodecathode voltage is also correspondingly small. This insures a relatively long life Of the tubes M and unusual reliability and efficiency of the system as a whole.

I claim:

1. The combination with a three-wire alternating current supply circuit and an individual translating device for each side of said circuit, of a transformer winding for each of said translating devices connected in series therewith between the neutral and the respective outer wire of said supply circuit, another transformer winding inductively interlinked with at least one of said windings aforementioned, an electron tube having its main path connected in series with said other winding across the outer wires of said supply circuit, and means to vary the conductivity of said electron tube for affording variations of the impedance of said windings first mentioned,

2. The combination with a three-Wire alternating current supply circuit and an individual translating device for each side of said circuit, of a center-tapped transformer winding, each half of said winding being connected in series with the respective translating device between the neutral and the respective outer wires of said supply circuit, another transformer winding inductively interlinked with said first mentioned winding, an electron tube having a main discharge path connected in series with said second mentioned winding across the outer wires of said supply circuit, and. means to vary the conductivity of said electron tube for affording variation of the impedance of the halves of said first mentioned winding.

3. The combination with a three-wire alternating current supply circuit and an individual translating device for each side of said circuit, of an individual transformer winding for each of said translating devices connected in series therewith between the neutral and the respective outer Wire of said supply circuit, another transformer winding inductively interlinked with at least one of said first mentioned windings, a pair of electron tubes having their main discharge paths connected inversely-parallel with each other and in series with said other winding across the outer wires of said supply circuit, and means to vary the conductivity of said electron tubes for affording variations of the impedance of said first mentioned windings.

4. The combination with a three-Wire alternating current supply circuit and an individual translating device for each side of said circuit, of a center-tapped transformer winding, each half of said winding being connected in series with the respective translating device between the neutral and the respective outer wires of said supply circuit, another transformer winding inductively interlinked with each half of said first mentioned winding, a pair of electron tubes having their main discharge paths connected inverselyparallel with each other and in series with said second mentioned winding across the outer Wires of said supply circuit, and means to vary the conductivity of said electron tubes for affording variation of the impedance of the halves of said first mentioned winding.

5. In a lighting system, the combination with a three-wire alternating current supply circuit and separate light sources of similar light emission characteristics connected to different sides of said circuit, of an individual transformer winding connected in series with the respective light source between the neutral and the corresponding outerwire of said supply circuit, another transformer winding inductively interlinked with at least one of said first'mentioned windings, an electron tube having its main path connected in series with said other winding across the outer wires of said supply circuit, and means to vary the conductivity of said electron tube for affording variations of the impedance of said first mentioned windings and of the light emitted by said sources.

6. In a lighting system, the combination with a three-wire alternating current supply circuit and separate light sources respectively connected to each side of said circuit, of a transformer winding individually connected in series with each of the respective light sources between the neutral wire and the corresponding outer wire of said supply circuit, another transformer winding inductively interlinked with at least one of said first mentioned windings, a pair of electron tubes having their main discharge paths connected inversely-parallel with each other and in series with said other winding across the outer wires of said supply circuit, and means to vary the conductivity of said electron tubes for afiording variations of the impedance of said first men'- tioned windings.

7. In a lighting system, the combination with a three-wire alternating current supply circuit and a separate light source connected to each side of said circuit, of a pair of like transformers, each transformer having a winding connected in series with one of said light sources between the neutral Wire and the corresponding outer wire of said supply circuit, each of said transformers having also another winding, an electron tube connected in series with the respective windings last mentioned across the outer wires of said supply circuit, and means to vary the conductivity of said electron tube for varying the impedance of said first mentioned windings to thereby vary the light emitted by the respective sources. a

8. In a lighting system, the combination with a three-wire alternating current supply circuit and a separate light source of similar light emission characteristics connected to different sides of said circuit, of a center-tapped transformer winding, each half of said winding being connected in series with one of the respective light sources between the neutral wire and the respec- 6. tive outer wires of said supply circuit, a transformer winding inductively interlinked with said first mentioned winding, a pair of electron tubes having their main discharge paths connected inversely-parallel with each other and in series with said second mentioned winding across the outer wires of said supply circuit, and means to vary the conductivity of said electron tubes for affording variation of the impedance of said first mentioned winding, to thereby vary simultaneously the voltages impressed upon said light sources by substantially equal amounts.

GEORGE J. LEXA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date Switzerland Apr. 15, 1933 Number Number 

